High-pressure laminates offer hard wear resistant surfaces that provide a thin layer for preventing moisture penetration. Because of their abrasion and moisture resistant properties, high-pressure laminates are widely used for commercial, home, and industrial surfaces such as counter tops, table tops, and floor panels. See, e.g., U.S. Pat. No. 4,390,580 (Donovan), issued Jun. 28, 1993 and U.S. Pat. No. 5,545,476 (O'Dell) issued Aug. 13, 1996.
These laminates are multilayer structures formed of several paper, or woven or non-woven fabric, layers embedded in one or more polymer resins. Suitable resins include melamine resins, phenolic resins, urea resins, epoxy resins, acrylic resins, urethane resins, ABS resins, polycarbonate resins, and in particular melamine-formaldehyde and phenol-formaldehyde resins. The paper or fabric is saturated with resin slurry consisting of a fine dispersion of resin, ceramic reinforcement and sometimes color additives in a water base. Once the slurry is applied to the surface of the paper or fabric, it is allowed to dry in air or in a drying oven. Generally, the top layer is formed from decorative paper saturated with a melamine-based slurry and the lower layers are formed from brown craft paper saturated with a phenol-based resin. Once dry, the layers are stacked in a heated press that cures the polymers and bonds the layers together to form the laminate.
In use, high-pressure laminates often come in contact with food and are a breeding ground for bacteria, fungi, and other microorganisms. Therefore, attempts have been made to develop high-pressure laminates exhibiting antimicrobial action. For example, the organic compound triclosan has been incorporated in countertops in an attempt to provide a surface exhibiting long lasting antimicrobial properties. However, microorganisms can develop resistance to organic compounds such as tricolosan. Moreover, the antimicrobial effects of triclosan decline over time as triclosan leaches out from the surface of the substrate. In addition, triclosan is believed to cause skin irritation. Furthermore, triclosan is believed to generate dioxin when burned, creating disposal problems.
There is therefore a need for a high-pressure laminate containing an antimicrobial composition that does not generate antibiotic resistance. There is also a need for a high-pressure laminate containing an antimicrobial that is nontoxic and safe for human contact. In addition, there is a need for a high-pressure laminate containing an antimicrobial agent that does not generate toxins when disposed of.